Doorcheck



Dec. 3, 1929. H. w. sHoNNARD DOORGHECK Filed Feb. 20, 1926 2 Sheets-Sheet 1 Dec. 3, 1929. H. w. sHoNNARD DOORCHEGK Filed Feb. 20. 1926 2 Sheets-Sheet 2 Snom/taz @QAM mi 'a l', Il", Aal',

Patented Dec. 3, 1929 UNITED STATES PATENT OFFICE HAR-OLD XV. SHONNARD, OI MONTCLAIR, NEW JERSEY, ASSIGNOR `TO ELEVATOR SUP- PLIES COMPANY, INC., A CORPORATION 0F NEW JERSEY DOORCHECK Application iled February 20, 1926. Serial No. 89,566.

The present invention relates to an improved form of door check whereby slamming of the door is prevented both in opening and closing the door. My improvement is particularly designed for use in connection with the type of sliding doors commonly used on elevator shafts, although it is to be understood that I do not limit myself to the application to doers of this or of any particular style or type.

Cylinder and piston door checks of the gen eral type to which this invention belongs have been used in which the slamming of the door when closed was prevented by the checking of a body of liquid, preferably oil, which is forced through a narrow adjustable opening on the down stroke of the piston. My present invention has relation to a novel construction applicable to door checks of this kind whereby they may be made effective against slamming in both directions by a simple and inexpensive means involving no change in that part of the device which acts to check the door when closed.

rihe invention is illustrated in a preferred form in the accompanying two sheets of drawing which together exhibit a longitudinal section of a door check embodying` my present improvement.

rlhis drawing shows one well known form of door check as heretofore used for preventing the slamming of the door or gate when closed, to which has been added my improvement; whereby this form of apparatus is made effective in opening as well as in closing 'the door or gate.

ln the well known door checks already in use, the closed cylinder 10 is provided with a head 11 which is pivotally attached to an appropriate fixed bracket shown in dotted lines at 12. Nithin an extension 13 to the head 11 there slides a piston 14: havin@r a piston rod 15 which passes through a stufhng box 16 in the cap 17., and is attached to a movable part connected with the door or gate, as

for instance, the swinging level' indicated in dotted lines at 18.

There is fixed to the movable piston rod l5 a spider 19 having a flange 20, against which bears the spring 21 the pressure of which operates to close the door. Of course, where the door is not closed automatically this spring may be omitted. It is also to be understood that, if desired, door closing means other than a spring may be used, without departing from the invention.

ln use the device shown is located with the head 11 lower than the cap 17 and the lower end accommodates a body of liquid, preferably oil, which acts as a retarding agent. Vt hen the door approaches its closed position, the oil below the piston lll is forced through the passage 22 and adjustable needle valve 23, thus iinding its way to the bach of the piston 11i, and through the passage 2li to the space within the outer cylinder 10.

ln setting out to produce the saine choching effect on the opening of the door, it is theoretically possible, of course, to simply provide the upper end of the cylinder extern sion 13 with an equipment similar to that -just described at the lower end.

Such a construction, however, would be diilicult and expensive to produce, as it would nec esitate the provision of a stuiling box like that shown at 16 placed in exact alignment with the stuffing boi; and would eX- Vclude all possibility of eccentric movement of the piston rod 15.

My invention is designed to obviate this difficulty and expense, by providing an effective checking means on the up stroke of the piston which is inexpensive in construction, which can be readily applied to the forms of checks already in use, and which will do away with an extra stuning box and permit eccentric movements of the piston rod 15 within the scope to be reasonably expected in practice.

For this purpose the cylindrical extension 13 of the head 11 is furnished with a head 25 having a central opening 26 the diameter of which is suciently greater than that of the piston rod to prevent all danger of r binding when the piston 14 moves back and forth. The resulting clearance around the rod 15 is clearly shown in the drawing.

Inside of the head 25, a'movable sleeve 27, made of fibre or other appropriate material, is carried upon the piston rod 15. This Y sleeve makes a sliding fit with the piston rod,

so that it moves back and forth with it.v

In ordert limit the extent to which this sleeve 27 may be moved away from the head 15%, headed screws' 28 are used which pass through openings in the sleeve 27 and are screwed into the head 25. The openings in Y the sleeve through which these screws pass are made larger than thescrews, so that a f limited lateral motion ofthe piston rod and sleeve kmay ,be permitted for the purposes above described.

Now when the door is Opened andthe piston 14 moves upward, the weight of the sleeve 27 prevents its upward movement so long as there isa free passage of the oil through the D '.eningl2`4, and consequently the movement the piston 14 is uite free while the opening 24 is clear. linen the piston 14 passes m thisv opening however, the resultant pressure forces the sleeve 27 against the inner face oflthe head 25, thus closing the opening 26 around the Ypiston rod; and further movement of thev piston can only ,be accomplished at the reduced speed permitted by the resistance of the oil as it isforced through the opening 29, the passage 30 and the adjustable needleV valve 31 into the space within the outer cylinder 10. This effectively checks the 4opening of the door toward the end of the opening movement, and prevents slamming.

vWhat I vclaim is` 1. In aldoor check, a cylinder having a` restricted oil exit at one end, a piston in said cylinder, a pistonrod operativelyV connected to'said piston, a'elosi-ng head at said end-of they cylinder havin a central opening somewhat larger than t e piston rod, and means adapted to` be operated by pressure of the the piston rod. Y

2.Ap.paratus as in claim 1 wherein the Y ymeans fOr @losing the space around thepiston rod is a sleeve on the piston rod making a suitable fit therewith. Y Y

- 3; Apparatus as in vclaim 1 wherein the means fbi' closing the space around the piston reid is asleeve on the piston v rod ina-king a suitable lit therewith, said sleeve having heeded ljetaining'mea-ns passing throughit and ixd' to the cylinder head, whereby the 'distance the Sleeve can be moved from the cylinder head is limited. i

4. In a door check, a dashpot cylinder, a 55 pi@ lilllelya @losing Vhead at one end of oil in one direction to close saidspace around HAROLD 1V. SHONNARD. 

